Exposure control system incorporating a master actuator

ABSTRACT

A photographic exposure control mechanism for use with a programmed exposure control system which automatically regulates both aperture area and exposure interval. The mechanism features a master actuator member which performs operation functions both before and during an exposure sequence and during cocking operations. In its preexposure mode, the master actuator is latched in an initial position which maintains the engagement of releasable magnetic armatures with appropriate contact areas of the electromagnets of the control system. Spring members are mounted upon and movable with the actuator member to assure appropriate contact of the armatures with the electromagnets. At the commencement of an exposure operation, the master actuator pivots to release an aperture regulating mechanism and cause the commencement of automatic aperture regulation. Simultaneously, the master actuator releases the engagement of the spring members from the armatures, thereby permitting their selective release by the electromagnets. The movement of the actuator may also be used to perform switching functions for a control circuit. The master actuator also functions during a cocking sequence to maneuver control elements and their associated armatures into appropriate reengagement with their respective electromagnets. In a preferred embodiment, the aperture is formed as an arm-shaped lever which is pivotally mounted upon the supporting structure of the exposure mechanism.

United States Patent Inventor Lawrence M. Douglas Boston, Mass. Appl. No. 837,682 Filed June 30. 1969 Patented July 27, 1971 Assignee Polaroid Corporation Cambridge. Mm.

EXPOSURE CONTROL SYSTEM INCORPORATING A MASTER ACTUATOR 47 Claims. 12 Drawing Figs.

Primary Examiner-Samuel S. Matthews Assistant Examiner-Joseph F. Peters, Jr.

Att0meysBrown and Mikulka, William D. Roberson and Gerald L. Smith ABSTRACT: A photographic exposure control mechanism for use with a programmed exposure control system which automatically regulates both aperture area and exposure interval. The mechanism features a master actuator member which performs operation functions both before and during an exposuresequence and during cocking operations. In its preexposure mode, the master actuator is latched in an initial position which maintains the engagement of releasable magnetic armatures with appropriate contact areas of the electromagnets of the control system. Spring members are mounted upon and movable with the actuator member to assure appropriate contact of the annatures with the electromagnets. At the com mencement of an exposure operation, the master actuator pivots to release an aperture regulating mechanism and cause the commencement of automatic aperture regulation. Simultaneously, the master actuator releases the engagement of the spring members from the armatures, thereby permitting their selective release by the electromagnets. The movement of the actuator may also be used to perform switching functions for a control circuit. The master actuator also functions during a cocking sequence to maneuver control elements and their as sociated armatures into appropriate reengagement with their respective electromagnets. In a preferred embodiment, the aperture is formed as an arm-shaped lever which is pivotally mounted upon the supporting structure of the exposure mechanism.

PATENTEU JUL 2 7 I971 SHEET 2 OF 6 INVENTOR. LAWRENCE M. DOUGLAS B E m M04 W and Mai at. M

ATTORNEYS PATENTED JUL 2 7 an SHEET 3 [IF 6 INVENTOR.

LAWRENCE M. DOUGLAS 4 fiww rg and 77Z1@a/@0 PATENTEDJULZTIQYI 3.595.152

SHEET 5 BF 6 INVENTOR. LAWRENCE M. DOUGLAS PATENTED JUL2'! wan sum s 0F 6 R. m m G W. U W o m M E c N n \NE 99 w m A M L Non m9 02 a L: w? 9% s8 w? N W amd Mala/L H" nd x, ATTORNEYS EXPOSURE CONTROL SYSTEM INCORPORATING .A MASTER ACTUATOR SUMMARY OF THE INVENTION The present invention is addressed to a photographic exposure control mechanism with a programmed control system which automatically regulates both the effective area of an exposure aperture and, in sequence, the exposure interval during which light passes through such aperture. At least two electiomagnets are incorporated within the control system. These electromagnets are selectively energized and 'deenergizcd by control circuitry to regulate the extent of movement of a spring loaded diaphragm assembly and, in sequence, to control the release of a shutter closing assembly following an appropriate exposure interval.

The instant exposure mechanism featuresa master actuator member which uniquely performs operational functions. both before and during an exposure sequence and during rccoeking operations. In a preexposure or standby operationalmode, the actuator may be latched to maintain the engagement of releasable magnetic armatures or keeper elements with appropriate contact areas of the electromagnets of the system. Resilient members are mounted upon and movable with the master actuator to assure an appropriate contact of the armatures with their respective electromagnets. At the commencement of an exposure operation, the actuator is unlatched for springdriven movement away from the armatures, thereby permitting .the' electromagncts to selectively release the keepers and control elements linked with them. During its movement, the actuator member carries out two control functions. As the member reaches a terminal position it mechanically unlatches and releases a spring loaded diaphragm element for a movement defining continuously variable apertures. Simultaneously, the actuator performs a switching function associated with the circuitry of the program control system.

As the exposure mechanism is recockcd theactuator is moved in an opposite direction. During this movement, the resilient members attached to the' actuator -pickup or reengage the previously released armatures or keeper elements and maneuver them' into reengagement with the electromagnets. The actuator, therefore, cocks or resets the electromagnctically actuated components of the control mechanism.

In a preferred embodiment, the actuator is formed as an arm-shaped lever. which is pivotally mounted upon thesupporting structure of the exposure mechanism. Extending across the electromagnet' assemblages, the arm is driven in a cocking direction from a point along its length located a substantial distance from the pivotal mount. As a consequence, a significant mechanical advantage is realized for providing the force necessary to maneuver the arm. This mechanical advantage is particularly helpful in automatic two-parameter exposure control systems where higher spring forces must be overcome as a result of the incorporation of a greater number of spring-loaded components. The mounting of the resilient members upon the master actuator advantageously provides an overtravel feature reducing the degree of accuracy required in maneuvering the armatures into their precxposure positions.

Another feature and object of the invention is to provide for a motorized cocking of the exposure mechanism. This motorized arrangement functions ideally to cause the cocking maneuver of the master actuator element. Further, the above noted mechanical advantage realized with the actuator configuration serves to advantageously lower the loads imposed upon a motor during a cocking cycle.

' In one embodiment of the invention, an electrically powered motor is coupled to drive a spooling cam which, in turn, provides a reciprocating translational or linear motion used for'maneuvering the master actuator and for causing the resetting or cocking of the shutter and diaphragm components to their preexposure positions.

A further object of the invention is to provide, in an exposure control mechanism having two or more armature elements which are held in initial positions by separate electromagnets upon energization thereof, novel means for retaining the armature elements and linkages associated therewith in close contact with the electromagnets until such energization.

Another object of the invention is to provide a fully automatic exposure control mechanism including a motorized cocking arrangement which is energized to cause the resetting of the mechanism components in a preexposure position.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the system and apparatus possessing the features, techniques and properties which are exemplified in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic, plan view of the aperture control assembly of an exposure mechanism according to the present invention, the various elements of the aperture regulating ar-, rangement being shown in a preexposure or cocked position, and certainof the elements being shown in phantom illustrating their alternate positions during an exposure sequence;

FIG. 2 is a diagrammatic, plan view of the aperture control assembly of FIG. 1 showing the positions of the various elements of the assembly during an exposure-sequence;

FIG. 3 is an enlarged fragmentary view showing a segment ofa braking mechanism illustrated inFIGS. l and 2; 1

FIG. 4 is a fragmentary view illustrated in FIG. 3 showing, however, the orientation of the braking structure during an aperture blade arresting procedure;

FIG. 5 is a diagrammatic, plan view of an exposure mechanism according to the invention showing shutter assembly elements for use with the control system of the invention, the various elements of the shutter assembly being shown in an initial preexposure or cocked position and portions of certain elements being shown in phantom to illustrate their orientation, during a cocking maneuver;

FIG. 6 is a diagrammatic, plan view of the shutter assembly of FIG. 5 showing the positions of the various elements of the shutter during an exposure interval;

FIG. 7 is a fragmentary side elcvational view showing a switching component of the exposure mechanism;

FIG. 8 is a fragmentary top view showing another switching component ofthe exposure mechanism;

FIG. 9 is a pictorial representation of a shutter release latch incorporated within the exposure mechanism of the instant invention;

FIG. 10 is an illustration showing, in perspective, the motorized arrangement for maneuvering the master actuator of the control mechanism;

FIG. 11 is a bottom view of a portion of the mechanism of FIG. 1, showing the slidable ram linkage extending from the motor assembly to the master actuator; and

FIG. 12 is a schematic circuit diagram of an electrical circuit operative in association with the exposure control mechanism of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS terval to provide accurate exposure regulation. Control over these exposure parameters is provided sequentially, commencing with regulation of the aperture defining movement of the elements of a diaphragm assembly. Following aperture control, a shutter mechanism is actuated to produce an cxposure interval responsive both to the aperture defined by the diaphragm assembly and to scene light levels. The description of the present exposure mechanism follows its mechanical operation from the cnmmenrpmpnt as a through the termination of exposure and cocking for a subsequent exposure. Following the above, an electrical circuit operable to control the exposure mechanism is described. Throughout the drawings, like reference numerals are used to denote like parts'among the several figures including the schematic switching counterparts in the circuit diagram of FIG. I2.

The shutter and diaphragm assemblies of the instant expo sure mechanism are mounted respectively on either side of a common base plate andare arranged thereon so as to selectively occlude light passing through a photographic optical path..Electromechanical linkages for controlling the exposure parameter assemblies are, for the most part, mounted within and upon either side of one section of the common base plate. Certain of these linkages will be found to function. in common with both modes of exposure parameter regulation. Consequently, they will appear in dotted form on certain of the drawings and in solid line form in drawings rep gesenting the opposite side of the base plate.

Referring to FIGS. 1 and 2, the aperture regulating assembly of the exposure mechanism is illustrated respectively in an orientation wherein the aperture blades are cocked in readiness for an exposure, andat a point in time following the commencement of an exposure sequence when an appropriate aperture has been definedin the figures, the ibase plate is identified generally at 10. Base plate I is formed having two principal levels 12 and 14. These levels meet and are joined at a riser or union represented at 16. The elevational difference between base portions 12 and I4 is minimal, basically serving to accommodate the above-mentioned linkages which are common to both aperture and shutter regulating operations. For the purpose of facilitating an understanding of the differen'ce of elevations of base- 10, in FIGS. 1 and 2, level 12 may be considered to be higher than level 14. B plate I0 is formed having a circular opening I8 coaxially ah H ed with the optical axis of the photographic apparatus within which the regulating mechanism is mounted. Opening 18 may be dimensioned having a diameter coextensive with the maximum aperture adjustment of the optical system. Aperture adjustment over the opening 18 is provided by a diaphragm arrangement formed of two aperture defining blades or elemepts ZO and 22. Formed of planar, opaque material, each of the blades 20 and 22 is configured having selectively contoured indentations or notches, the edges of which are shown respectively at 24 and 26. The notches within each of the aperture blades are shaped and arranged so as to cooperate when overlapped to define aperture openings, as indicated at 28, which are formed about the axis of the optical path of the photographic apparatus.

Blades 20 and 22 are mounted for rotation upon the base plate 10 at pivot studs, respectively shown at 30 and 32 which extend into and are supported by base plate portion 14.

To provide a coaetion between each of the aperture blades, externally meshing spur gears 34 and 36 are journaled respectively over the shafts of studs 30 and 32 and fixed respectively to blades 20 and 22. The spur gears 34 and 36 permit a uniform synchronous and relative coaction between aperture forming blades 20 and 22. Inasmuch as the aperture blades are linked for mutually opposed rotation through gears 34 and 36, only one of the blades need be driven to impart rotation to both. Accordingly, a singular wire blade loading spring 38 is mounted within the assembly to bias the blades for oppositely directed pivotal movement. Spring 38 is slidably wound about pivot stud 30 and includes a stationary end fixed to base plate 10 by a tab 40 extending therefrom. The flexedtransitional end of spring 38 is positioned in biasing relationshipagainst an aperture spring stud 42 secured to the surface of blade 20. Rotational force exerted by spring 38 against blade 20 serves to impose a corresponding oppositely directed rotational force upon blade 22 through the geared mechanical" linkage between the blades. In the initial or cocked position of the blades depicted in FIG. I, a minimum aperture which. the blades are called upon to define is present. of course, when in this position the blades may entirely occlude the passage of light. To provide for an adequate separation of the'aperture blades from this minimum aperture position while maintaining structural compactness, semicircular indentations are formed respectively within blades 20 and 22 at 44and 46.

A further examination of the shape ofaperturc blade '20 reveals an outwardly extending flange portion or vane 48 within which is formed a progressively enlarging opening or slot 50. Flange portion 48 is beveled inwardly at 52 such that its rearward surface'passes in relatively close proximityto an annular mounting 54 configured to retain a light sensing element such asja photovoltaic cell or lightdependentresistor. This photosensitive element is positioned within mounting 54 so as to assume an outward orientation permitting it to witness I scene illumination. In this orientation, the photosensitive element will be positioned with-respect to flange portion 48 such that the amount of scene light which it receives is regulated by the instant area of the enlarging slot 50 presented before it at a given time during an exposure sequence. Slot 50 is selectively configured for attenuating light reaching a photocell at 54 in correspondence with the aperture defining position of blades 20 and 22. With the above scanning arrangement, a control circuitry operable with the mechanism of the invention may be made responsive to relative aperture and scene light during an exposure sequence.

The coacting aperture blades 20 and 22 are held in the cocked or preexposure initial position illustrated in FIG. 1 by a release latch 56. Positioned on the opposite side of base portion 12, the latch 56 is mounted for rotation about a pivotal stud 58 fixed to the base plate. The aperture blade retaining latch is configurated having, a latching tip 60 extendable through an opening in riser 16. Tip 60 relcasably engages blade 20 by virtue of this selective insertion within a slot positioned in an outwardly bent flange 62 formed in the upward edge of blade 20. At its opposite extremity, latch56'is configured having an outwardly extending flange portion 64. The aperture release latch is biased for rotational movement, causing engagement with aperture flange 62, by a wire spring 66 slidably wound about stud 58 and having one end fixed to base portion 12 and the opposite end configured to hook about the body of latch 56 (see FIG. 5 and 6). The extent of rotational travel of latch 56 is limited by the periphery of an opening in riser 16 through which its tip 60 passes.

Flange portion 64 or release latch 56 extends through an opening 68 in base portion 12 in a position suitable for permitting its coaetion with a loading arm 70 which functions as a master actuator. Loading arm 70 is positioned on the opposite side of base portion 12, and accordingly is moreelearly illus trated in FIGS. 5 and 6. Mounted for rotation upon and pivotal about a pivot bushing or stud 72 fixed to the base, the arm extends downwardly to a position coincident with base opening 68. The lower tip of arm 70 is bent to form a flange portion 74 which extends through opening 68. A wire spring 76, slidably wound about pivotal mount 72, functions to urge the arm 70 into a pivotal movement about bushing 72 sufficient to cause the contact of its flange 74 with flange 64 of aperture release latch 56. Spring 76 is mounted having its transitional end fixed to a tab 78 formed in arm 70 and its opposite end held relatively stationary by abutment against upfrom its contact with flange 74 to form a second resilient keeper contact member 90.

As illustrated in FIGS. 1 and 5, loading arm 70 is held prior to exposure in a retracted position by a loading arm release latch 92. Latch 92 is pivotally mounted upon astud 94 fixed,

' in turn, to base plate portion 12. The latchfis configured having a latching tip 96 arranged to engage a tab 98 extending from the rearward edge of loading arm 70. Latch 92 is biased for rotation toward engagement with tab 98 by a wire spring 100. Spring 100 is configured having one side abutting and biased against the mounting bracket 106 of a release button 102 and a transitional side arranged to hook over the upward edge of arm 70. I

Theupward edge of latch 92 is additionally shaped to include a circular cam surface 104 which is configured and arranged for cooperation with the underside of release button mounting bracket 106. Release button bracket 106 is mounted copivotally with arm at bushing 72. The interaction ofspring and camming tip 104 oflatch 92 provides an upward bias against the bottom side ofbracket 106 imparting an-upward return action to the release button 102. Upward travel of the button 102 is limited by its engagement with a tab bent outwardly from base'plate portion 12. A downward extension 108 of button 102 functions to actuate a switching 'member S used for energizing the circuitry of a control system.

. Turning to FIG. 7, switch S, is shown to include an electrically insulated base molding 110 fixed to a tab extension 112 of base plate portion 14. Base molding 110 supports upper and lowerswitch contact leaves illustratedrespectively at 114 and .116.- Intermediate leaves 114 and 116 is a common contact leaf 118 whichis normally biased for contact with leaf 116. Common contact leaf 118 is held away from contact with leaf 116 by virtue of its engagement with extension 108 of release button 102. A. depression of release button 102 will cause a release of electrical contact between leaves 114 and 118 and electrical engagement between leaves 118 and 116. I 1 Returning to the preexposure or cocked orientation of the loading arm 70 in FIG. 1, the engagement of release latch .92 with the loading arm causes the retention of the arm 70 in orientation wherein its keeper, contact members 88 and 90 respectively are in stressed contactv against movable magnetic armatures orkeepers 120 and 122. Keepers 120 and. 122 are pivotally coupled with linkages which permit their movement into and away from abutting contact respectively against the poles of electromagnets 124 and 126. Electromagnets 124 and 126 are mounted within base plate portion 12 and incorporate respectively pole members 128 and 130 including coil windings 132 and 134.

'Keepers 120 and 122 function as magnetic armatures with the elcctromagnets 124 and 126. To assure'a proper seating of the'keepers upon the electromagnets, the stressed resilient contact members cause their compressive engagement against pole members 128 and 130. This compressive retention must be maintained during a cocked preexposure orientation of the apparatus. The forces exerted during such periods by resilient members 88 and 90 are ideally contained by the relatively simple mechanical latching engagement of latch 92 with loading arm 70. Release of this latching engagement requires a relatively low manually exerted pressure upon button 102.

Looking to FIGS. 5 and 8, an additional master actuator function of the loading arm 70 is revealed. When retained in the cocked position illustrated by virtue of its engagement with latch 92, loading arm 70 causes the closure ofa switch 8;, having a normally open free position. Referring to FIG. 8,

' switch S is shown to be formed having an electrically insulated mounting base 136 fixed to base plate portion 14. lnsulated base 136 retains two resilient contact leaves 138 and 140 in a normally opened or noncontacting position. Switch S is oriented, however, with respect to the face of loading arm 70 such that the loading arm holds the switch S in a closed orientation while held in a retracted or preexposure position by latch 92. As seen in FIG. 8, the arm 70 functions to urge contact leaf 138 against leaf 140. To assure the electrical integrity of the switching arrangement, an electrically insulated surface shown at 142 is riveted over a portionof the contacting surface of loading arm 70. During shutter operation, as loading arm 70 is released for rotation, surface 142 moves out of engagement with contact leaf 138-and permits switch-S to open. Proper elevational alignment of the arm 70 with respect to contact leaf 138 is provided by a plastic strip 144 molded integrally with base 136 and extending along the path of travel of arm 70. 7

An exposure sequence is commenced with the manual depression of release button 102. As button 102 moves downward, its supporting bracket 106 cams against the camming edge 104 of release latch 92-imparting rotation to it against the bias of spring100. This rotation results in the release of latching tip 96 from engagement with tab 98 on loading arm 70. Such release ofloading arm 70 will permit its spring loaded rotation which, in turn, causes its flange end portion 74 to strike the cooperating flange 64 of the aperture blade release latch 56. The resultant impact will rotate or drive latch 56 about its pivot 58 in a direction causing its latching tip 60 to disengage from flange 62 of aperture blade 20. The resultant impact will rotate or drive latch 56 about its pivot 58 in a direction causing its latching tip 60 to disengage from flange 62 of aperture blade 20, The resultant orientations of loading arm 70, loading arm'release latch 92 and aperture blade release latch 56 are illustrated in connection with FIGS. 2 and 6. Depression of release button 102 also causes the closure of contact leaf 118 against leaf 116 of switch S which, as described in connection with FIG. 12, permits the energization of electromagnets 124 and 126. When thus energized, electromagnets 124 and .126 magnetically retain keepers 120 and 122 in abutting position against their pole members. I

With the disengagement of aperture release latch 56 from flange 62 of aperture blade 20, aperture blades 20 and 22 will rotate under the bias of spring 38 to define a gradually enlarging aperture opening 28. Withthe movement of blade 20, variable opening 50 in flange portion 48 moves across or scans" a photosensitive element at 50 to selectively attenuate scene light permitted to impinge upon the element.

The signal thus derived by the photosensitive element represents a function not only of the level of light perceived, 120 also of the relative orientation of blades 20 and 22 and, accordingly, the relative aperture defined at 28. i l

A consideration of the-configuration and mutual interlinkage of the aperture blades 20 and 22 reveals that the blades define a continuously variable aperture rather than an incremental or stepped variation as they separateunder the bias of spring 38. To halt the motion of the blades at an appropriate aperture, a mechanical braking arrangement is utilized'which is actuated in response to the decnergization ofelectromagnet 126, Since the aperture blades 20 and 22 are mutually linked by gears 34 and 36, the braking arrangement, shown generally at 150, need work with only one of the blades, for instance, blade 22. The braking system is fully described and illustrated in a copending application for US Pat. Ser. No. 784,064 by Lawrence M. Douglas, entitled Aperture Defining Exposure Control System", filed Dec. 16, 1968.

Referring to FIGS. 1 and 3, braking arrangement is illustrated in an orientation permitting the free pivotal movement of the aperture blades 20 and 22. The brake comprises a mounting bracket 152 fixed to base plate portion 14 by rivets or the like as at 154. Mounting bracket 152 is configured to position the braking elements of the arrangement a select distance from the surface of aperture blade 22. Mounting bracket 152 is structured to support an axle 156 in a plane parallel with the surface of aperture blade 22. Pivotally mounted upon axle 156 is a braking'member formed having a lever portion 158 extending from axle 156 towards the surface of blade 22 and an integrally connected retracting portion 160 extending oppositely therefrom.

Lever portion 158 has a length greater than the selected distance from axle 156 to the surface of blade 22. A central opening is formed within the braking member to permit the insertion of a wire spring 162. Spring 162 is configured and arranged to bias lever portion 158 towards the surface of aperture blade 122. Toward the outer tip of lever portion 158 an opening is formed in the braking member which functions to retain a cylindrically shaped insert 164 formed of a brake-shoe material having a higher coefficient of kinetic friction with respect to the material from which the blade 22 is formed. The surface of insert 164 is held away from the surface of aperture blade 22 as a result of a downward pressure exerted upon retraction portion 160 by the tip 172 of a changeover arm shown generally at 170. An upward rotation of the changeover arm, however, will release this downward pressure exerted by tip 172, permitting the lever portion 158 to pivot about axis 156 into contactwith the surface of blade 22, thereby arresting its motion to define a select aperture. The resultant orientation of the components of the brake assembly following its release is illustrated in connection with FIGS. 2 and 4.

Positioned on the aperture blade side of base plate portion 12, changeover arm I70 mechanically associates the energized status of electromagnet 126 with the operation of brake assembly 150. The arm is pivotally mounted upon a stud 174 depending from the base plate 12 and is rotatably secured on stud 174 by a retainer ring 176. One leg 178 of the changeover arm is configured and dimensioned for pivotally supporting magnetizable keeper 122 for movement into and away from an abutting position against electromagnet 126. A second leg 180 of the arm extends to braking tip 172 which, as earlier described, functions to actuate brake 150. Leg 180 also is configured having an integral extension 182 terminating in a flanged tip portion 184 which extends through an opening 186 in base plate portion 14. Flange 184 provides an exposure control function on the opposite side of the base plate assembly. Leg 180 also supports an electrically insulated cylindrical bearing member 188 which extends outwardly from its surface. A rotational bias is imparted to the changeover arm 170 by a wire spring 190 slidably mounted over stud 174, having a transitional end which abuts against a tab 192 extending from leg 180 and a stationary end which abuts against a tab 194 on the base plate.

In the orientation shown in HO. 1, changeover arm 170 is held against the bias of its spring I90 by the keeper 122. Keeper 122 is maintained in position against electromagnet 126 either by the energization of the magnet or by keeper contact member 90 of loading arm 70. During an exposure sequence, the loading arm 70 is rotated such that contact member 90 is no longer in contact with keeper 122 and the keeper is retained in abutting position against the pole member 130 until such time as coil 134 is deenergized. At that instant, changeover arm 170 rotates causing tip 172 to release brake 150 and elevate flange 184. The release position of arm 170 is illustrated in FIG. 2. Cylindrical bearing member 190 on the changeover arm 170 is positioned in operative relationship with the common contact leaf 200 of a dual terminal switch 8,. Switch 8, includes an insulative mounting base 202 mounted upon base plate 10. Common contact leaf 200 extends sufficiently over changeover arm 170 to contact and bear against cylindrical bearing member 188. In the orientation of FIG. 1, common contact leaf 200 is held against leaf 204 of switch S by virtue of its abutment against cylindrical bearing member 188. As changeover arm 170 is permitted to rotate, common contact 200, by virtue of its preselected spring bias, is allowed to move into contact against leaf 206 as illustrated in FIG. 2.

The release of keeper 122 by electromagnet 126 permits changeover arm 170 not only to brake the aperture blades 20 and 22 at an appropriate aperture, but also causes the commencement of exposure interval regulation by virtue of the raising of flange I84 and the causing of the closing of switch S contact leaves 200 and 206. A shutter mechanism responding to the movement of the changeover arm 170 is portrayed in connection with FIGS. 5, 6 and 9, FIGS. and 6 representing an opposite side of the base plate l0 assembly heretofore discussed. In HO. 5, the shutter mechanism is shown in a cocked, preexposure orientation, while in FIG. 6 the shutter mechanism is depicted in a status assumed while terminating an exposure interval. I

The shutter portrayed in the figures utilizes a pair of opaque, planar shutter blades. These blades sequentially uncover and cover the optical path of a photographic apparatus. At the commencement of an exposure interval, a first of these blades, termed the opening blade" moves to a position causing the unblocking of the optical path of the camera. Following an appropriately timed interval of exposure, a second blade termed as the closing blade" is released for movement to a position causing a covering of the optical path. An exposure interval is derived as the time elapsed between the opening and closing of the shutter blades and is controlled bythe timed release of the closing blade in accordance with a control system program.

The opening blade of the shutter assembly is illustrated at 230 as a wedge-shaped segment of a circle, the apex of the wedge being mounted for rotation about a pivotal stud 232 depending from base plate portion 14. As illustrated in the cocked portrayal of the shutter mechanism of FIG. 5, blade 230 is configured having a planar, opaque portion extensible over the opening 18 of the exposure mechanism optical path. The planar face of opening blade 230 also'is formed having an annular opening 234 of at least equal diameter with opening 18. Openings 234 and 18 are oriented having equal radial spacing from the pivot at stud 232. Positioned over and mounted coaxially with the opening blade 230 is a planar, opaque closing blade 236 configured coradially with the outward edge of blade 230 and having a surface area sufficient to occlude light passing through opening 234 when it is rotated into appropriate position. A retainer ring 238 is positioned over stud 232 to maintain the blades in position thereupon.

With the configuration described, the blades 230 and 236 will selectively occlude light passing through optical path opening 18 as they are rotated about their mutual pivot at 232. To provide for the rotation of the blades during an exposure, each is biased for codirectional rotation by a spring. For instance, blade 230 is biased for rotation into its orientation shown in FIG. 6 by a wire spring 240 centrally wound about a spring hanger 242. Spring 240 has a stationary side, the tip of which bears against a ledge 244 ofa spring tension adjustment comb 246. A transitional side of the spring 240 is shown extending from hanger 242 to assert a rotational force upon opening blade 230 through pressure exerted against a radial flange 248 formed integrally with the blade. Closing blade 236 is biased for rotation about pivot 232 by a wire spring 250. Spring 250 is slidably wound about a spring hanger 252. The stationary side of spring 250' is retained within a selected notch as at 245 formed within comb 256. A transitional side of spring 250 is connected to a radial edge of closing blade 236 by a tab member 256 extending from its lowermost edge. Thus tensioned between comb 246 and tab 256, the spring 250 biases the closing blade 236 for rotation codirectional with blade 230.

Opening blade 230 and closing blade 236 are retained in a preexposure, cocked orientation by virtue of their engagement respectively with flange 184 of changeover arm 170 and a closing blade release latch 258. Flange 184 of changeover arm 170 is illustrated extending from the opposite side of base plate 10 through rectangular opening 186. In cocked orientation, the flange 184 abuts against the forward edge of a tab 260 protruding outwardly and radially from the curved upper edge of opening blade 230. The tab 260 also as an outwardly bent flange portion 262 which cooperates in abutting relationship with a corresponding notch 264 formed within closing blade 236. Closing blade release latch 258, pictured separately in H6. 9, is mounted for rotation upon an axle 266 fixed to the base plate at one side of opening 68. The latch straddles base plate portion 12, one side forming a latching arm 268, the tip of which is arranged to abut against a corresponding flange 270 formed in an outer edge of closing blade 236. The opposite side 272 of latch 258 is provided with an opening 274 adapted to receive a connector for providing pivotal connection with keeper 120. When keeper is positioned in abutting contact with electromagnet 124 either by virtue of the energization of the electromagnet or by contact member 88 of loading arm 70, latching arm 268 of the latch 258 retains the closing blade in the standby orientation shown in FIG. 5. Because of its particular configuration, the latch permits the commencement of a closing movement of blade 236 at the instant of release of keeper 120 from clectromagnet 124. The released pivotal movement of arm 268 complements the release movement of blade 236. Such an arrangement provides an improved response of the shutter mechanism to a change in the status of energization of elcctromagnet 124.

An exposure interval is commenced with the deenergization of electromagnet 126 and the resultant movement of changeover arm 170 to the orientation shown in FIG. 2. This rotation simultaneously causes a rotational lifting of flanged tip portion 184 of the arm and the release of its engagement with tab 260 of opening blade 230. Turning to FIGS. and 6, the

orientations of blade 230 respectively before and during an exposure interval are portrayed. As blade 230 rotates under the bias of spring 240, the forward striking surface 276 of a flange 278 formed at the edge of blade 230 moves in an arcuate path towards tripping engagement with a spring loaded switch actuating assembly shown generally at 280. Assembly 280 includes a switch actuating lever 282 mounted for rotation about a pivot pin 284 and held on by a retainer ring 286. Lever 282, as viewed in FIGS. 5 and 6, is biased for clockwise rotation by a wire spring 288. Spring 288 is slidably wound about pivot pin 284 and is arranged having a stationary end abutting against a tab 290 depending from base plate portion 14 and a transitional end abutting against a tab 292 bent outwardly from 282. One end of lever 282 supports a cylindrical, electrically insulative bearing member 294 which functions to actuate a switch S,. Thc other side of lever 282 is formed to define two leg portions 296 and 298 bent, respectively, at 300 and 302 to elevate their outer tip areas. An escape leaf 304 is pivotally mounted on a stud 306 depending from the elevated tip portion of leg 296. The pivotal connection is completed by a retainer ring 308 positioned over the leaf 304 and stud 306. Fixed to the underside of leaf 304, a push stud 310 is positioned to provide for selective abutment against one edge ofa notch 312 formed in the elevated tip of leg portion 298. A U- shaped wire spring 314 having one side fixed to leaf 304 by tabs 316 and the other side stressed to abut against an upwardly bent wall forming the bend 302 in tip 298 functions to bias push stud 310 against the wall of notch 312. Escape leaf 304 is additionally configured having a striking tip 318 fastened from an inwardly bent tip section ofits movable side.

Assembly 280 is held in an orientation illustrated in FIG. 5 as a result of the abutment of push stud 310 against the inwardly facing upper edge 320 ofa shutter recocking arm 322. Edge 320 is formed in arm 322 just above a slot 324 configured and dimensioned of width sufficient to permit the slidable insertion of push stud 310. Assembly 280 is maintained in the preexposure orientation illustrated in FIG. 5 by virtue of the rotative force exerted by spring 288 which is counteracted by edge 320 of the arm 322.

The preexposure orientation of the assembly 280 provides for a select switching configuration at switches S and S These switches are formed having an electrically insulative mounting base 330 fixed in appropriate position upon base plate portion 14. Base 330 supports a first switching arrange ment 8,, including upper and lower contact leaves shown respectively at 332 and 334. Between the latter contact leaves is a common contact member 336 engageable with bearing member 294 ofassembly 280 and resiliently biased for contact with leaf 334 upon the downward rotation of member 294. Beneath the first switching arrangement, base 330 supports a second switching arrangement S formed of upper contact leaf 338 and lower leaf 340. The latter switching leaves are resilient and mounted in a normally open or free configuration. Upper contact leaf 338 is configured having a length sufficient to permit its engagement with a lower portion of cylindrical bearing member 294. As a consequence, with the downward rotation of assembly 280, switch leaves 338 and 340 will be brought into engagement. An electrically insulative pin 342 extending from base plate portion 14 limits the downward travel of contact leaves 338 and 340 as well as the rotational travel of assembly 280.

When released shutter blade 230 rotates, the forward striking surface 276 of flange 278 will strike the tip 318 of escape leaf 304. As a result, the leaf 304 will be pivoted downwardly against the bias of spring 314 until push stud 310 is aligned with the opening of notch 312 formed within recocking arm 322. When this orientation is reached, assembly 280 rotates under the bias of spring 288 and push stud 310 moves into contact with the back edge of notch 312. When this activity occurs, assembly 280 is adjusted to the orientation illustrated in FIG. 6 wherein contact leaves 336 and 334 of switch 8,, have been permitted to close and bearing member 294 has caused closure of switch S contact leaves 338 and 340. As striking surface 276 of blade 2 30 strikes tip 318, the opening blade is brought to a gradual halt, its motion terminating when the forward edge of blade extension 350 comes into contact with an arresting tab 352 extending from base plate portion 14. The latter position of blade 230 permits the uncovering of the optical path by bringing annular opening 234 substantially into registry with opening 18.

The shutter mechanism remains open in the orientation described until such time as keeper is released from electromagnet 124. It follows, therefore, that the deenergization of elcctromagnet 124 terminates the exposure interval. As keeper member 120 is released, the force exerted by closing blade spring 250 will cause the simultaneous upward pivotal motion of both blade 236 and closing blade releaselateh 258. An orientation of the shutter components at such an instant is shown in FIG. 6. Blade 236 will continue to pivot until its notch 264 engages and abuts against outwardly bent flange portion 262 of opening blade 230. When so oriented, closing blade 236 will entirely cover openings 18 and 234 to terminate an exposure interval.

Following the termination of an exposure interval, an exposure cycle is completed by causing the repositioning of all exposure mechanism elements to a cocked, preexposure orientation. Referring to FIGS. 1, 2, 10 and 11, a unique recocking arrangement for the exposure mechanism of the invention is illustrated. The recocking assembly provides for two basic operations, namely, a movement of loading arm 70 rearwardly to an orientation permitting its relatching with release latch 92 and a repositioning of aperture blades 20 and 22 and shutter blades 230 and 236 to their preexposure orientations. Since only these two operations are required of the cocking assembly, the exposure mechanism may readily incorporate a motorized drive system.

In FIGS. 1, 2 and 10, an electric drive motor and its housing 360 are illustrated. Housing 360, incorporating the motor, is mounted upon base plate portion 14. When energized, this motor causes the rotation of a spooling cam 362 rotatably mounted beneath housing 360. Rotation is imparted into the spooling cam 362 by a spooling cam driven gear 364 journaled over a cam bushing 366. Driven gear 366 is powered from a drive pinion 368 which, in turn, is operated through a reduction gear assembly 370, coupled to the electric motor. Reduction gear assembly 370 is shown only in fragmented and general fashion, its construction being conventional in the art. The opposite side of spooling cam 362 is journaled for rotation into a bracket 372 fixed to the underside of housing 360 by panhead screws as at 374.

Spooling cam 362 is grooved conventionally and is assembled in conjunction with a cam collar 376 which incorporates a cam follower 378 slidably engaged within the grooves of the spooling cam. Cam follower 378 is illustrated in FIG. 1. The cam follower includes a cylindrical stern portion 380 and is retained within the cam collar 376 by a retainer cap 382 (FIG. 10). Retainer cap 382 incorporates a cylindrical stud portion 384 within which the stem portion 380 of cam follower 378 is journaled for rotative mounting. The retainer cap is mounted upon the forward face of cam collar 376 by rivets as at 386.

From the foregoing, it will be seen that as spooling cam 362 is rotated, cam follower 378 causes the IPrinrnrmfin tan-m tional movement of collar 376 along its lengthwise dimension. For one cocking operation this motion is used to maneuver loading arm 70 from its release position as shown in FlG. 2 to its latched orientation shown in FIG. 1. The cam collar motion is transferred by a loading ram 390 extending across the bottom of base plate 10. Ram 390 is attached to the cam collar 376 by a screw 392 passing through the lower flange portion of the ram. The opposite tip of ram 390 is formed as an outwardly bent flange 394 within which is threaded an oval point set screw 396. Ram 390 is slidably mounted upon the bottom of base plate 10 by shoulder rivets 398 and 400 attached to the underside of the base plate and extending, respectively, through slots 402 and 404 formed in the bottom surface of the ram. Retainer rings as at-406 and 408 hold the ram 390 in slidable relationship upon the shoulder rivets. (See P10. 11).

Movement of cam collar 376 from one terminus of spooling cam 362 to the other will cause the set screw 396 to engage a lower portion ofloading arm 70 and urge the arm rearwardly a distance sufficient to permit the tip 96 of loadingarm release latch 92 to cam over tab 98 and resume a rclatching engagement therewith. As the loading arm returns to its cocked position, resilient keeper contact member 88 will reengage keeper 120 and move it into appropriate abutment with the poles of electromagnet 124i Simultaneously, keeper contact member 90 will recngage keeper 122 mounted upon changeover arm 170 and urge it into reengagement with electromagnet 126.

Contact members 88 and 90 are configured such that a select amount of overtravel is permitted in performing the above repositioning functions. This not only allows for a reliable reengagement of the keepers with their electromagnets as well as a reliable relatching with latch 92, but also permits a desirable amount of latitude in the design of the spooling cam drive mechanism. The extent of forward motion of the loading ram 390 is indicated in phantom at 395 in H0. 1 of the drawings. A return of the changeover arm 170 to its precxposure position by loading arm 70, in turn, causes a release of brake 150 from engagement with aperture blade 22. Similarly,

closing blade release latch 258 is repositioned as well as the release latch 184 for opening blade 230. y,

The movement of the loading arm 70 into its preexposure position also causes leaf 138 of switch to return into electrical contact with leaf 140. Similarly, the cocking movement of changeover arm 170 causes the reengagement of leaves 200 and 204 of switch S and the disengagement of leaf 200 from leaf 206.

A particularly advantageous aspect of the cocking maneuver provided with loading arm 70 lies in the mechanical advantage or leverage gained by pushing the arm from a position remotely displaced from its axial pivot pint at 174. Note that set screw 396 makes contact with the arm at its lowermost region. Since the loading arm 70 performs several resetting functions in its return travel, it must overcome relatively high spring loadings. The mechanical advantage derived with the arrangement lessens the loads otherwise imposed upon the motor unit at 360. Spooling cam 362 is designed such that following a select number of revolutions, cam collar 376 will have moved along the length of the cam and returned once.

To return aperture blades 20 and 22 to their preexposure orientation as illustrated in P16. 1, an aperture cocking arm 414 is rotatably mounted on extension 416 of housing 360. This rotatable mount is provided by an axle 418 journaled within extension 416 and fixed in driven relationship with cocking arm 414. Arm 414 is configured having a camming slot 420 slidable over the stem 380 of the motor driven spooling cam assembly. Arm 414 also supports a lifting stud 422 positioned thereon for selective engagement with a flange 424 formed in the edge of aperture blade 20.

Thus configured, aperture cocking arm 414 represents a variation of a bell crank pivoted at 418 and driven from the camming relationship between stem portion 380 of the spooling cam assembly and slot 420. Energization of the motor at 360 causes the stud 384 to move between the termini of spooling cam 362 which, in turn, causes lifting stud 422 to engage flange 424 of aperture blade 20 and return it to a cocked orientation. An orientation of the arm 414 as it reaches the apex of this return movement is shown in phantom in FIG. 1 at 414. Because of the mechanical linkage of blades 20 and 22, blade 22 is returned to its cocked orientation simultaneously with the return of blade 20. As blade 20 is returned to the aforesaid cocked position, the tip of aperture release latch 56 cams over flange 62 along the upper edge of blade 20 until the tip of the latch reengages a slot positioned therein. As the stem 380 of the spooling cam arrangement returns to its initial position, both loading ram 390 and aperture cocking arm 414 return to the orientations of FIG. 2.

Recocking movement of aperture cocking arm 414 provides for a simultaneous and corresponding movement of shutter recocking arm 322. Driving force forrotating the arm 322 is derived from the movement of axle 418journaled within housing extension 416.

Referring to FIG. 5, shutter recocking arm 322 is shown having an inwardly extending tip 326 configured and arranged to contact and cam against the flange 248 of opening blade 230 upon rotation of the arm. As the arm 322 rotates to the phantom position 322', opening blade 230 is pivoted against the bias of spring 240 into relatching engagement with flange 184 of changeover arm 170. As blade 230 pivots toward reengagement with flange 184, its outwardly bent flange portion 262 will have reengaged notch 264 in closing blade 236 to cause the simultaneous repositioning of both the opening and closing blades. As shutter cocking arm 322 rotates to the position shown in phantom at 322, tip 326 having moved to its position at 326, flange 262 will have reengaged notch 264 and the changeover arm 170 will have been rotated by loading arm 70 to cause the gradual repositioning of flange 184 in position holding opening blade 230 in a preexposure orientation. Similarly, closing blade latch 258 cams against the outer edge of closing blade 236 to reassert its latching engagement with flange 270. Latch 258 is held in its final position by virtue of the engagement of its keeper with contact 'member 88 ofloading arm 70.

At the commencement of a recocking maneuver, switch actuating assembly 280 has the orientation illustrated in FIG. 6, the contact leaves 336 and 334 of switch 8,, being held in a closed position. During a cocking movement, arm 322 rotates to a position wherein its notch 324 moves out of engagement with push stud 310. As arm 322 is rotated in a return motion, the inwardly facing upper edge 320 of the arm will reenegage push stud 310 and move switch actuating lever 282 into the orientation shown in FIG. 5. As arm 322 reaches the terminal position illustrated in that figure, contact leaves 334 and 336 of switch S, are separated while contact leaves 336 and 332 are joined. As discussed in detail hereinafter, this switching action in conjunction with the operation of switch S, provides for the properly timed energization of the electric motor at 360.

A control circuit which may be used with the abovedescribed exposure mechanism is illustrated in connection with FIG. 12. This circuit provides for control of the aperture and shutter regulating mechanism in accordance with a predetermined exposure program, for instance, one in which aperture and exposure interval parameters are related to variations in scene light level values in a proportion of less than one-to-one. A detailed description of the circuit may be found in a copending US. application for Pat. Ser. No. 837688, entitled Exposure Control System, under the inventorship of John P. Burgarella, filed concurrently with the instant application.

The control system evaluates scene light levels with a light sensing circuit shown generally at 450. Circuit 450 includes a photovoltaic cell 452 which may be'positioned within annular mounting 54, as earlier described, and oriented to evaluate the light levels of a scene coincident with the field of view of the lens system of the photographic apparatus. This cell operates with the earlier described progressively enlarging opening 50 of flange portion or vane 48 formed within aperture blade 20.

Accordingly, scene light reaching the cell 452 is altered in synchronism and corresponding variation with an adjustment of aperture size. Cell 452 is coupled with an amplifier stage 454 from alonginput lines 456 and 458. The amplifier 454 is one sometimes referred to in the art as an operational amplifier." For the present application it is of a differential variety, preferably in practical, miniaturized form. When considered ideally, the amplifier 454 has an infinite gain and infinite input impedance and a zero output impedance. By virtue of a feedback path between the output 460 of amplifier 454 and its input, the cell 452 may operate into an apparent low input impedance. The feedback path arrangement includes a potentiometer 462 having a wiper arm 464 connected to line 466. The potentiometer provides a trimming function for exposure interval timing operations. Feedback path line 466 is coupled with a timing capacitor C and with a feedback resistor R To provide for the exclusive insertion of feedback resistor R into the feedback path 466 during an aperture regulating mode of operation, a two-position switch S is coupled from junction 468 and bypass line 470 by joining its contacts "a" and in an exposure interval regulating mode of operation, the common contact terminal of switch S is closed between terminals a'and c," thereby inserting a line 472 to bypass re sistor R,. Since cell 452 operates in conjunction with a low input impedance, it is permitted to function in a current mode and its output current permits the generation of a voltage across the feedback resistor R which is witnessed at the output line 460. The voltage signal present at output line 460 of the light sensing circuitry is introduced through a calibrating resistor R to a second amplification stage 474. Amplifier 474 may be structured identically with the operational amplifier 454 of the light sensitive circuitry 450. Accordingly, it is of a differential variety having input lines 476 and 478 and an output at 480. A feedback path including line 482 and a variable resistor R is connected between the output 480 and input line 476 of the amplifier. Variable resistor R provides a means for varying the gain of amplifier 474. Accordingly, the resistor R may be used to adjust the level of the output signal of light sensing circuitry 450 in accordance with the sensitometric properties of the film or photosensitive material being used with the exposure control system. lndicia may be provided with the wiper arm of the resistor for indicating proper settings corresponding to a variety of film speeds.

Having been adjusted at the amplification stage 474, the light responsive signal at output 480 is present at a common output terminal 484 to which is coupled parallel output lines 486 and 488.

Power supply to the above-described light sensing circuitry 450 and second amplification stage 474 is derived from a DC source such as a battery 492, the positive and negative terminals of which are coupled respectively to positive and nega tive bus lines 494 and 496. Electrical energy is supplied into the latter bus lines by closure of the common terminal of switch S between its contacts a-b. The differential amplification stages 454 and 474 require the presence of a reference level or ground. This ground level is derived along a third bus line shown at 498. Note that amplifiers 454 and 474 respectively are connected with reference level bus 498 from along-lines 500 and 502, to bus 494 from line 504 and its branches 506 and 508, and to bus 496 from lines 510 and 512.

When the control system is operated to regulate the aperture mechanism, the output signal at common output terminal 484 will represent both the illumination on photovoltaic cell 452 and the relative orientation of aperture blades 20 and 22. This signal is represented from along line 486 to an adjusting circuit shown generally at 514. Adjusting circuit 514 alters the signal such that it may function to fire a voltage sensitive trigger circuit shown generally at 516 in accordance with a predetermined exposure program selectively interrelating aperture and exposure interval in accordance with scene light. An exemplary program is one described and illustrated in the above-referenced copending application of John P. Burgarella.

The adjustment provided by subsidiary circuit 514 is one which joins the light sensitive circuit from line 486 with a ramp signal. As a prelude to the operation of the circuit 514, however, the brightness signal from line 486 must be scaled so as to be capable of functioning with a triggering level for voltage sensitive circuit 516. This firing or triggering level is generally about one-half of the voltage between buses 496 and 498. For the brightness signal from line 486 and to be used with trigger circuit 516, a DC level shift must be provided. in this regard, note that the output of amplifier 474 is at the ground reference level of bus 498 and the triggering level for the circuit 516 is at a voltage value substantially below the ground reference. To provide the requisite level shift, a pair of resistors R and R are incorporated in line 486 between common terminal 484 and bus 496. These resistors are chosen having resistance values such that a voltage is provided at a junction 518 between them which is substantially smaller than the triggering level established at the triggering circuit 516. With such an arrangement,-a signal passing through the amplification stage 474 goes positive with respect to the ground and appears in attenuated or scaled down form at junction 518. A line 520 couples a capacitor C between junction 518 and an input terminal 522 of trigger circuit 516. A resistor R is coupled between line 520 and bus 498 by line 524. Capacitor C is selectively bypassed by a shunt path 526 incorporating a normally closed switch S When switch S is open, capacitor C is charged through resistor R by a signal representing an association or addition of the scaled brightness level signal and a ramp signal.

Resistors R and R, form part of the return path for the charging signal and that the charging signal through resistor R is additive with respect to the brightness level signal and a ramp signal.

Resistors R and R form part of the return path for the charging signal and that the charging signal through resistor R is additive with respect to the brightness signal at junction 518. To provide a proper addition of the above signals, the initiation of the charging sequence on capacitor C should be coincident with the initiation of the scanning of photocell 452 by the slot 50 within vane 48 of aperture blade 20.

This operation is ideally performed in the exposure mechanism of the invention by the cooperative arrangement of switch S; and loading arm 70 as described in connection with FIGS. 5, 6 and 8. The length of switch 5;, contact leaf 138 may be adjusted in correspondence with the travel of the arm 70 as it is released such that the contact leaves 138 and 140 open at the instant that the loading arm causes aperture release latch 56 to release blades 20 and 22 for coactive pivoting. it will be recalled that the latch 56 is pivoted into a blade releasing orientation as the flange 74 of arm 70 strikes corresponding fiange 64 of latch 56. The accuracy of the opening of the contacts of switch S is assured with the above arrangement inasmuch as the spring dynamics involved in causing arm 70 to rotate have an insignificant influence on the timing of the opening of switch S and the release of the aperture defining elements 20 and 22. No exposure regulation occurs until arm 70 reaches its blade releasing terminal position.

During a recocking sequence, the arm 70 is returned to its preexposure orientation wherein it is held in position by release latch 92. This movement also provides for the reclosing of switch S as the insulative surface 142 of the arm 70 moves under and recontacts contact leaf 138. Such closure serves the function of resetting capacitor C for sequential operation.

The voltage buildup at capacitor C is presented along line 520 to the input terminal 522 of trigger circuit 516. Circuit 516 may be of a Schmitt-type trigger circuit which has an input that is a normally nonconducting stage and an output which is a normally conducting stage. When the entire circuit is energized from battery 492 and through the closure of the contact of switch S between terminals a" and "b, the output stage of trigger circuit 516 will permit current to continu- OllfilV flnw Yhrnnnh on" 111 kahn lvt L.. A!

through the path including lines 528, 530 and 532. Coil 134 has been described earlier as a component of electromagnet 126 which selectively retains keeper 172 of changeover arm 170 in a prebraking position. When coil 134 is deenergized, the changeover arm is permitted to rotate and actuate brake mechanism 150. The functional coupling of coil 134 with the aperture mechanism depicted in block fashion at 534 is indicated by dashed linkage 536. When the normally nonconducting stage of trigger circuit 516 receives a signal at terminal 522 which has reached a predetermined threshold value, the trigger circuit 516 will cause its normally conducting stage to switch to a nonconducting status. As a result, coil 134 is deenergized to regulate the aperture mechanism. The deenergization of coil 134 also converts the exposure mechanism and the control circuitry to operation in an exposure interval regulating mode. At the commencement of shutter interval regulation, changeover arm 170 causes the common contact 200 of switch S to move into contact with leaf 206. This switching adjustment would be represented in FIG. 12 as a movement of the contact terminal of switch S to a position uniting terminals a" and b." The contact member of switch S remains in an orientation coupling terminals *a" and b" throughout the regulation of an exposure interval.

At the commencement of the exposure interval timing, photocell 452 has been scanned by the opening 50 in the vane 48 of the aperture blade 20. Accordingly, cell 452 generates an output signal which is responsive both to the earlier selected aperture and to the light level of a scene. This output signal ultimately is used to determine the exposure interval defined between the uncovering of the aperture by shutter blade 230 and its covering by shutter blade 236. When operated to determine the exposure interval parameter, the feedback path 466 of light sensitive circuitry 450 excludes resistor R and includes a capacitor C,. This alteration is provided with the actuation of switch S Appropriate switching action is provided by changeover arm 170 simultaneously with the release of shutter opening blade 230. With the capacitor feedback arrangement, photovoltaic cell 452 is permitted to operate in a current mode, a current generated by the cell being limited substantially by its own internal impedance. Under such loading, the photovoltaic cell 452 is capable of forming a desirable linear output in response to scene lighting. During operation, any difference of potential supplied by the photovoltaic cell 452 across input leads 456 and 458 causes a voltage to be produced at feedback path line 466 of opposite polarity to the voltage at line 458 (or the output end of capacitor C As a consequence, the feedback path provides a substantially instantaneous feedback signal of opposite polarity which serves to counteract any differential signal voltage impressed by cell452 across the input terminals 456 and 458. The relatively low signal voltages at the input of amplifier 454 which are present with the relatively low signal current deriving from photovoltaic cell 452 are acted upon by the correspondingly high gain characteristic of the amplifier. Thus, although the amplifier 454 has a high input impedance, the photocell 452, when connected in the system described, experiences only a very low impedance. Therefore, the current output of the photovoltaic cell 452 is directed into the feedback path.

The potentiometer arrangement at 462 provides a trimming function for the exposure interval timing parameter. In this regard the wiper arm 464 may be arranged to be manually adjusted by an operator to insert a lighten or darken adjustment into the system. Inasmuch as the potentiometer 462 is inserted between the output line 460 and reference level 498, the voltage buildup at the output of the amplifier 454 is varied in accordance with the position of wiper arm 464. The signal present at output 460 of the light sensing circuitry is introduced through calibrating resistor R into the second amplification stage 474. At stage 474, the gain of the signal is adjusted, as before, in accordance with the sensitometric properties of the photosensitive material being used with the expo- .mns nflffll cuetpm Nntp in thi: rmmrrl that the second amplification stage 474 functions with both operational modes of the control system. Generally, resistor R is selected for calibrating the exposure interval control portion of the system. This control parameter is determined with respect to a previously automatically selected aperture opening and any minor variation in aperture from the program is accommodated by the calibrated exposure interval control. Accordingly, adequate exposure precision is maintained with the precise calibration of only the exposure interval parameter circuitry. For calibration purposes, resistor R may be selected having a value accommodating any tolerances in sensitivity of photovoltaic cell 452, tolerances in the capacitance values of capacitor C I or in the exposure interval voltage sensitive trig gering circuitry.

From the second amplification stage 474, the light responsive signal is directed from common output terminal 484 through line 488 for introduction to a voltage sensitive trigger circuit depicted generally at block 536. Inasmuch as trigger circuits 5 16 and 536 are driven from a single source, means must be provided to assure their energization in proper sequence. The sequencing of their operation is achieved by raising the voltage level required for firing trigger circuit 536. This level adjustment is accomplished by the insertion of a diode 538 in path 488. Diode 538 drains off a portion of the voltage signal present in path 488. It is preferred that the diode 538 be of the solid state silicon variety inasmuch as this form requires about one-half volt threshold signal before assuming a substantially fully conductive state. The diode further accommodates any signal excursions which may cause the inadvertent firing oftrigger circuit 536.

Somewhat similar to trigger circuit 516, trigger circuit 536 is a Schmitt-type which permits the continuous energization of a coil 132 until the receipt at its input terminal 450 of a signal of predetermined level. Coil 132 is a component of electromagnet 124. When energized during an exposure sequence, the coil 132 causes the retention of keeper in abutting contact with the poles of electromagnet 124 and, as a result, retains the shutter closing blade 236 in an orientation permitting the passage of light through the exposure aperture. The electromechanical linkage between coil 132 and the shutter mechanism shown in functional block form at 542 is depicted by dashed line 544. Trigger circuit 536 is formed having an output stage that is normally conducting and permits the passage of current between buses 494 and 498 from along lines 546, 548 and 550. The circuit 536 also includes a normally not conducting stage which upon receipt of a signal of predetermined threshold value at terminal 540 causes the switching of the normally conducting stage to a nonconducting status. This switching action, deenergizes coil 132, permitting electromagnet 124 to cause the release of shutter closing blade 236. Power switch S, remains closed to maintain the electrical union of its terminals a" and b throughout the exposure interval regulating operation of the circuit by virtue of the continued depression of release button 102.

Attention is now turned to the orientation within the control circuit of the two identical Schmitt-type triggering circuits 516 and 536. The symmetrical arrangement of these circuits across the power supply permits the establishment of the reference or ground level of bus 498 without the use of a tapped power supply. This form of power supply would otherwise be required for the operation of differential amplifier stages 454 and 474. The balance of ground level bus 498 between power buses 494 and 496 is maintained as long as the normally conducting stages of circuits 516 and 536 are active or in a conductive state and the coils 134 and 132 respectively coupled with them are energized. During an exposure sequence, however, circuit 516 will be triggered to deenergize coil 134 before circuit 536 is triggered. Without a form of compensation in the circuit 516, the symmetrical arrangement between buses 494 and 496 will be interrupted and negate the reference level contribution of bus 498. To compensate for the change in state of coil 134, a transistor Q and resistor R are coupled between ground bus 498 and bus 496 to form a bypass across coil I34 and the normally conducting stage of trigger circuit 516. Transistor Q, is formed having base, emitter and collector electrodes, respectively at 55211, 552e and 552C. The base 552k of transistor 0, is coupled to one side of coil 134 at line 530, its collector electrode 552c is coupled to bus 498 and its emitter electrode 552e is coupled with resistor R to bus 496. Thus couple d, the transistor Q, and resistor R, constitute an emitter-follower arrangement with the normally conducting stage of circuit 16. During the energization of coil 134, a low voltage line 530 will maintain transistor Q, in a nonconducting status. As the circuit 516 is triggered and coil I34 is deenergized; the voltage level at line 530 will begin to rise. This voltage is present at the base 552b of transistor 0,. As it reaches an appropriate level, conduction is permitted at the base-emitter junction of Q, to shunt current otherwise passing through coil 134 through the bypass circuit. A silicon transistor is recommended for use as transistor 0, inasmuch as its threshold operational characteristics permit it to remain inoperative during the conduction of the normally conductive state of trigger circuit 516. Resistor R, has a value somewhat equivalent to the resistance imposed at the coil 134.

As switch S, is closed to supply power to the entire control circuit, it is important that trigger circuit 516 be in appropriate alignment such that its normally conducting stage immediately conducts. Sincethe trigger circuit may assume a somewhat random status following an exposure, it is preferred to insert a means for aligning it concurrently with the closing of the contact of switch S, against its terminals a and Such alignment is provided by a capacitor C, inserted between junction 518 and power bus 496. Capacitor C causes the input 522 of circuit 5I6 to be held momentarily at the minus potential of bus terminal 496.

Operational amplifiers such as depicted at 454 may require the presence of a small biasing current at their input terminals in order to provide a more accurate and effective operation. Such a biasing current is purposely inserted into the input side of the amplifier 454 through an attenuation network indicated generally at 554. Network 554 includes resistors R,,, R,, and R,,,. Resistors R, and R are coupled on line 556 extending between bus 494 and bus 498. Resistor R,,, is coupled from a junction between resistors R,, and R, to line 466 between line 458 and line 472. The resistance values within network 545 are selected to insert a low threshold level bias current into the amplifier 454. The insertion of a low bias current is effective to broaden photosensitive characteristics of the exposure control system. Since the photovoltaic cell 452 may be called upon to detect very low light levels, the biasing current inserted by the network permits substantially all the signal current generated by the photocell to be inserted into the feedback path of amplifier 454. Without the biasing current supplied by the network, such very low level signals would be drawn to the amplifier rather than to the feedback path.

The circuit arrangement thus far described provides automatic exposure control under conventional ambient illumination. For transient scene illumination, such as that supplied by flashbulbs and the like, an auxiliary timing network is incorporated within the circuitry to supplement the ambient mode circuitry. This network is indicated generally at 558. The control system circuitry is prepared for making a flash exposure by manually setting a switch as at S, to a closed position. Switch S,, is connected with line 560 between power supply buses 494 and 498. Connected in series with switch 5,, is a flashbulb or the like 562.

Some adaptations of the exposure mechanism heretofore described may include means for inserting a follow-focus adjustment for flash illuminated exposures. With this adjustment, relative aperture is selected in accordance with the flash source-to-subject distance. The aperture mechanism at 542 would include, therefore, means for halting the opening movement of the aperture blades and .22 in accordance with a follow-focus determination. Following this initial adjustment to aperture terminal travel position, network 558 causes the shutter closing blade to release at least at the termination of a predetermined fixed exposure interval.

The fixed exposure interval provided by the network 558 is selected to permit the shutter to remain open, for instance, over the light generating period ofa flashbulb. Under more normal conditions of flash illumination, the exposure interval will be terminated by the photosensing circuitry ofthc control system before the time period defined by network 558 is reached, hence the term auxiliary timing network.

For the control circuitry and the exposure mechanism to operate with flashbulb illumination, trigger circuit 516 must be fired to release changeover arm I70, and as a result, shutter opening blade 230. Under conditions of illumination wherein the signal derived from light sensing circuit 450 is inadequate in and of itself to fire the trigger circuit, capacitor C is called upon to fire circuit 516 after an interval permitting aperture blades 20 and 22 to open to their full extent, for instance about 25 milliseconds. Capacitor C is charged to an appropriate triggering voltage by the earlier discussed ramp signal through line 524 and resistor R,,. Resistor R, and capacitor C are linked to form an R-C timing circuit, voltage buildup from which is presented to the input terminal 522.

As discussed in connection with FIG. 6, the opening movement of blade 230 causes the actuating assembly 280 to close contact leaves 338 and 340 of a switch With the closing of switch S flashbulb 562 is fired. The closing of switch S also energizes the auxiliary timing network 558. Under most conditions of flash mode operation, the photosensing circuit functions as described above in response to the illumination of flashbulb 562 and to film speed (as inserted in resistor R to cause a controlled covering of the aperture blade through the release of closing blade 236. Should this not be the case, auxiliary network 558 deenergizes coil I32 and terminates the exposure following the select exposure interval, for instance 40 milliseconds.

Auxiliary timing network 558 includes an R-C timing-integrating arrangement including a resistor R,, and capacitor C, coupled between line 560 and bus 498, respectively, by lines 564 and 568. At the junction between resistor R,, and capacitor C,,, a line 570 is connected extending from line 568 to a transistor 0 Transistor O is shown having base, collector and emitter electrodes respectively at 572b, 5720 and 572e. Base electrode 572i) is coupled with line 570. Collector electrode 562c is coupled to line 564 and emitter electrode 572e is coupled with line 488 and, therefore, with the input terminal of trigger circuit 536.

With the closing of switch S capacitor C, is charged through resistor R,,. The resultant voltage buildup is presented across the base-emitter junction of the transistor Q, and as it reaches a preselected triggering level, transistor 0 is forward biased to fire triggering circuit 536 from its input terminal 540. Upon receipt of the triggering signal, circuit 536 functions as earlier described to cause the release of shutter closing blade 236. A resistor R is inserted in line 560 between its junction with line 564 and flashbulb connection 562 to function as a limiting resistor. When flash 562 is fired, the current drains occasioned through the flash circuit are limited by resistor R to a value such that the internal impedance drop in battery 492 is not so great as to cause an inadvertent firing of trigger circuit 536.

Following the release of shutter closing blade 236, manually actuated release button 102 is released to return to its preexposure position under the bias of springs I00 and 76. As this occurs, the common contact leaf 118 of switch S, moves from its contact with lower contact leaf 116 to reassert its contact with upper contact leaf 114. This activity would be represented in FIG. I2 as the movement of the contact member of switch S, from its orientation connecting terminals a and "b" to an orientation coupling terminals a" and c. As a result of the release of shutter opening blade 230, switch actuating assembly 280 causes switch S, to change from the orientation depicted in FIG. 5 to the orientation depleted in FIG. 6, wherein common contact member 336 is electrically coupled with lower leaf 340. The latter orientation is represented in FIG. I2 by a positioning of the contact member of switch S, between terminals 11" and h Thrahnvn described orientation of switches S and S following the relezusc of shutter closing blade 236 will permit power to be supplied from battery 492 to a motor 574 coupled in line 576; Motor 574 is mounted within the earlier described housing at 360 for driving spooling cam 362 as disclosed above. MOtor 574 drives the spooling cam through one complete cocking cycle and, in performing this function, remains energized until actuating assembly 280 returns to a preexposure position which, in turn, causes switch S to resume the orientation shown in FIG. 5. The latter orientation is depicted in FIG. 12 as a closing of the contact member of switch 5., against ter minals a and This switching action inserts line 578 into the energizing circuit of motor 574 to provide a dynamic braking action. Such dynamic braking provides for the proper repositioning of spooling cam collar 376 at the end of a cocking cycle.

Since certain changes may be made in the above exposure control mechanism without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

lclaim:

1. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture, comprising:

a first magnetic armature movable between initial and terminal positions;

a first electromagnct selectively energizable at different levels to retain said first armature in its initial position and to permit said first armature to move to its terminal position;

first means responsive to the movement of said first armature from its initial position to its terminal position to effect the determination ofa first photographic function;

a second magnetic armature movable between initial and terminal positions;

a second electromagnct energizable at different levels to retain said second armature in its initial position and to permit said second armature to move to its terminal position;

second means responsive to the movement of said second armature from its initial position to effect the determination ofa second photographic function; and

a master actuator movable in one direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets and movable in another direction to cause the commencement of said first photographic function.

2. The exposure control mechanism ofclaim l in which said master actuator includes resilient means contactable with said first and second magnetic armatures for causing their comprcssive engagement respectively with said first and second electromagnets when in said initial positions.

3. The exposure control mechanism of claim 2 including retaining means for holding said master actuator in a position compressibly retaining said first and second magnetic armatures in said initial positions.

4. The exposure control mechanism of claim 3 including manually operated means for selectively releasing said retain' ing means from holding engagement with said master actuator.

5. The exposure control mechanism of claim 2 wherein said resilient means are configured and arranged to permit said master actuator to continue to be moved in said one direction after causing the said engagement of said armatures with said electromagnets.

6. The exposure control mechanism of claim 2 wherein said master actuator movement is pivotal about an axial mounting positioned substantially at one end thereof.

7 The eimnsure control mechanism ofclaim Sin which:

said master actuator includes resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when in said initial positions; and

including a mechanical latch selectively engageable with said master actuator when said actuator provides for the compressive engagement of said first and second magnetic armatures.

8. The exposure control mechanism of claim 7 wherein said resilient means are configured and arranged to permit said master actuator to continue to be moved in said one direction after causing the said engagement of said armatures with said electromagnets.

9. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture, comprising:

a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween;

a first magnetic armature movable between initial and terminal positions;

a first electromagnct selectively energizable at different levels to retain said first armature in its initial position and to cause said first armature to move to its terminal position; I

first means responsive to the movement of said first armature from its initial position for controlling the said movement of said diaphragm assembly element to effect a determination of exposure aperture area;

a second magnetic armature movable between initial and terminal positions;

a second electromagnct energizable at different levels to retain said second armature in its initial position and to cause said second armature to move to its terminal position;

second means responsive to the movement of said second armature from its initial position to effect the determination of said exposure interval; and

a master actuator movable in one direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets and movable in another direction to cause said diaphragm assembly element to move from said initial position.

10. The exposure control mechanism of claim 9 in which said master actuator is configured having resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when in said initial positions.

11. The exposure control mechanism of claim 10 including manually releasable first latch means for mechanically retaining said master actuator in a preexposure position compressibly retaining said first and second armatures in said initial positions.

12. The exposure control mechanism of claim 11 wherein said resilient means are configured and arranged to permit said master actuator to be moved in said one direction after causing the said compressive engagement of said armature with said electromagnets and following said manually releasable first latch means mechanical engagement.

13. The exposure control mechanism of claim 11 including switch means mounted for actuation by said master actuator simultaneously as said actuator causes the commencement of movement of said diaphragm blade element for causing the initiation of a signal coincident with the said commencement of said element movement.

14. The exposure control mechanism of claim 11 including second latch means mechanically engageable with said diaphragm assembly element to retain it in said initial position configured and arranged with respect to said master actuator to respond to its said other directional movement for seleclively releasing said element for movement from said initial position.

15. The exposure control mechanism of claim 14 wherein said second latch means is configured and arranged to be driven out of said mechanical engagement with said diaphragm assembly element upon contact with said master actuator during its said other directional movement.

16. The exposure control mechanism of claim l including switch means mounted for actuation by said master actuator simultaneously with said second latch means contact for causing the initiation of a signal substantially in coincidence with the said release of said diaphragm element.

17. The exposure control mechanism of claim ll wherein said master actuator is configured and arranged for pivotal movement about an axial mounting positioned substantially at one end thereof.

18. The exposure control mechanism of claim 17 including cocking means operative to engage said master actuator at a position remote from said axial mounting for causing said one directional movement while deriving leverage about said mounting.

19. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture comprising:

a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween;

a first magnetic armature movable between initial and terminal positions;

a first electromagnet selectively energizable at different levels to retain said first armature in its initial position and to cause said first armature to move to its terminal position;

first means responsive to the movement of said first armature from its initial position for controlling the said movement of said diaphragm assembly element to effect a determination of exposure aperture area;

a second magnetic armature movable between initial and terminal positions;

a second electromagnet energizable at different levels to retain said second armature in its initial position and to cause said second armature to move to its terminal position;

second means responsive to the movement of said second armature from its initial position to effect the determination of said exposure interval; master actuator movable about a fixed pivot in a first direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagncts and movable in a second direction to cause said diaphragm assembly element to move from said initial position; and

cocking means operative to selectively engage said master actuator for causing said pivotal movement in said first direction following an exposure interval and for returning said diaphragm element to said initial position.

20. The exposure control mechanism of claim 19 in which said master actuator includes resilient means contactablc with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when retained in said initial positions by said master actuator.

21. The exposure control mechanism of claim 20 including manually releasable first latch means for mechanically retain ing said master actuator in a preexposure position compressibly retaining said first and second armatures in said initial positions.

22. The exposure control mechanism of claim 21 wherein said cocking means is operative to engage said master actuator at a position remote from said pivot so as to achieve a leverage for lowering the force values required to cause said first directional movement.

23. The exposure control mechanism of claim 22 in which said cocking means includes:

driven means actuable to provide said engagement with said master actuator and for urging said diaphragm element 5 into said initial position; and

driving means for selectively actuating said driven means following a said exposure interval,

24. The exposure mechanism of claim 22 in which said cocking means includes:

an electric motor selectively energizable to provide a rota tional motion;

driven means for converting said rotational motion into linear motion rcciprocable within predetermined limits of travel;and

means for selectively coupling said driven means with said master actuator at said remote position to cause said first directional movement. I

25. The exposure control mechanism of claim 24 wherein 2() said driven means limit of travel is predetermined to permit said master actuator to be moved in said first direction a select distance after causing the said compressive engagement of said armature with said electromagnets and following said manually releasable first latch means engagement.

26. The exposure control mechanism of claim 24 wherein said driven means includes:

a spooling cam coupled in driven relationship with said electric motor; and

cam follower means associated with said spooling cam for deriving said reciprocal motion.

27. The exposure control mechanism of claim 24 wherein said coupling means includes a ram member linked at one end with said driven means and engageable at another end with 3 said master actuator at said remote position for selectively transferring said linear motion to said master actuator when moving in said first direction.

28. The exposure control mechanism of claim 27 wherein said ram member includes adjustable means for selectively varying the maximum extent of said first directional movement of said master actuator.

29. The exposure control mechanism of claim 26 wherein said cocking means includes:

a pivotally mounted bell crank assembly having a first portion linked in driven relationship with said cam follower means and a second portion engageable with said diaphragm assembly movable element for causing the return of said element to said initial position during the S0 actuation of said driven means.

30. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the e:: posure interval during which light passes through such aperture, comprising:

a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween;

a regulator arm movable between initial and terminal posh tions;

means for biasing said regulator arm away from said initial position;

a first magnetic armature mounted upon said regulator arm and movable therewith between said initial and terminal positions;

a first electromagnet engageable for magnetic coupling with said first armature when said regulator arm is in said initial position and selectively energizable at different levels to retain said arm in its initial position by magnetic coupling therewith and to release said first armature to cause said arm to move under said bias to said terminal position;

means responsive to the movement of said regulator arm from its initial position for controlling said movement of said diaphragm assembly element to effect a determination of exposure aperture area;

a shutter assembly having at least one element movable from initialto terminal positions toeffect the determination of said exposure interval; v

meansfor biasing said shutter element between said initial and terminal positions;

a shutter regulator movable from an initial position retaining said shutter element in said initial position to a rest 7 position permitting the said shutter element movement;

a second magnetic armature mounted upon said shutter regulator and movable therewith between said initial and rest positions;

a second electromagnet engageable for magnetic coupling g with said second armature when said regulator is in said initial position and selectively energizable' at different levels to retain said regulator in its initial position by said magnetic coupling and to release said second armature to permit said regulator to move toward said rest position;

a master actuator movable about a fixed pivot in a first direction'to maneuver said first and secondmagnetic arniatures respectively into engagement, for magnetic coupling with said first and second electromagnets, thereby causing a corresponding movement of said regu-. lator arm and said shutter regulator to said initial posi tions, and movable in a second direction to cause said diaphragm assembly elementto move from said initial position; and r i t' I cocking'means operative to selectively engage'said master actuator for causing said-pivotal movement in said first direction following an exposure'interval and for returning said diaphragm element and said shutter element to said initial positions. 1 v

31 The exposure control mechanism of claim 30 wherein said masteractuator includes resilient means engageable with said first and second magnetic armatures for urging said armatures into said compressive engagement during said first directional movement. I Y

32. The exposure control mechanism of claim 31 including master actuator latch means for selectively retaining said master actuator in a preexposure position retaining said first and second armatures in said compressive engagement with said first and second electromagnets and actuable to release said master actuator for'movement in said second direction.

33. The exposure control mechanism of claim 31 including:

a masteractuator latch pivotally biased for mechanical latching engagement with said actuator when in aprecxposure position retaining said first and second armatures insaid compressive engagement; and I a manually actuable releasemember configured and arranged with respect to said master actuator latch to pivot said latch against said bias so as to cause the release of said mechanical latching engagement for initiating said second directional movement.

34. The exposure control mechanism of claim 32 including diaphragm latch means responsive to said master actuator second directional movement for releasably retaining said diaphragm assembly element in said initial position although actuated by said master actuator.

35. The exposure control mechanism of claim 32 including I a diaphragm latch pivotally mounted within said mechanism and biased toward latching engagement with said diaphragm element when in said initial position, said latch being configured and arranged to be driven out of said engagement by said master actuator in response to the second directional movement thereto.

36. The exposure control mechanism of claim 32 in which said shutter regulator includes an arm member engageable with said shutter assembly element when in said initial position and mounted for movement toward said raised position codirectionally'with the movement of said element.

, 37. The exposure control mechanism of claim 32 wherein said cocking means is operative to engage said master actuator ata position remote fro m'said pivot so as to achieve a leverage for lowering the force values required. to cause said first J 7 38. An exposuremechanism for; a photographic camera comprising: 7

a camera housing for mounting the optical path instrumentalities of said camera; I u

a diaphragm mechanism including at least two aperture blade elements mounted upon said housing, said elements being mutually and synchronously coactivc and releasablc formovement between cocked and rest terminal positions defining minimum and maximumexposure apertures v first spring means for urging said blade elements between said terminal positions;

regulator means movable from cocked to terminal orientationsfor halting the movement of said aperture blade elements at positions defining select exposure apertures; s second spring means for urging said regulator means from said cocked toward said terminal orientations;

a first elcctromagnet mounted upon said housing in an orientation permitting its engagement for magnetic coupling with said regulator means when in said cocked orientation, said elcctromagnet being selectively energizable for controlling-the said movement of said regulatormcans; 1 g

a shutter mechanism having at least one element movable from a cocked to a blocking terminal orientation relative to said optical path to effect the determination of the interval of an exposure; I 1 1 a third spring means for urging said shutter element between said cocked andterminal positions; I

shutter latch means mounted upon said housing and movable into orientations for retaining said shutter element in and releasing it from said cocked position; g

.a second electromagnetconfigured and arranged on said housing to permit its-engagement for magnetic coupling with said shutter latch means and being selectively energizablc for controlling said latch meansrnovcment from said element retaining orientation;

a master actuator rotatably mounted upon said housing for movement about a fixed pivot in first and second directions and configured and arranged to cause the engagement for magnetic coupling of said first electromag net with said regulator means and of said second electromagnet with said shutter latch means when moved in said first direction, and to cause the said release of said aperture 'blade elements when moved in said second direction;

manual release means for causing said master actuator to move in said second direction; and i cocking means mounted upon said housing for selectively causing said master actuator to move in said first direction and for repositioning said aperture blade elements to cocked terminal positions and said shutter mechanism element to said cocked terminal orientation.

39. The exposure mechanism of claim 38 in which said master actuator is configured having resilient means, contactable with said regulator means and said shutter latch means for causing their engagement respectively with said first and second elcctromagnets when in said cocked positions.

40. The exposure mechanism of claim 39 wherein said cocking means is operative to engage said master actuator at a position remote from its pivotal mounting so as to achieve a leverage for lowering force values required to cause said first directional movement.

4L'The exposure mechanism of claim 40 including a master actuator latch pivotally mounted upon said camera housing and biased for mechanical latching engagement with said master actuator when said actuator is in a preexposure orientation retaining said regulator means and said shutter latch means in said engagement for magneticcoupling.

42. The exposure mechanism of claim 40 including diaphragm latch means responsive to said master actuator second directional movement for releasably retaining said aperture blade elements in said cocked position until actuated by said master actuator.

43. The exposure mechanism of claim 42 including switch means mounted upon said housing and oriented for actuation by said master actuator simultaneously with said diaphragm latch means contact for causing the initiation of a signal simultaneously with said release of said aperture blade elements.

44. The exposure mechanism of claim 42 in which said diaphragm latch means comprises:

a latching element configured having a latching tip and a striking flange, said tip being engageable with at least one said aperture blade element and said flange being contactable with said master actuator at or during second directional movement; and

means for biasing said element into pivotal engagement with said aperture blade element.

45. The exposure mechanism of claim 42 in which said cocking means includes:

electric motor selectively energizable to provide a rotational motion;

driven means for converting said rotational motion into linear motion reciprocablc within predetermined limits of travel;

means for selectively coupling said driven means with said master actuator remote position to cause said first directional movement;

a pivotally mounted bell crank assembly having a first portion linked with said driven means and a second portion engageable with at least one said aperture blade element for selectively positioning said element in said cocked position; and

a cocking arm linked in driven relationship with said bell crank assembly and configured and arranged on said housing for urging said shutter element into said cocked orientation.

46 The exposure mechanism of claim 42 in which said regulation means and said shutter latch means include mag netic armatures for effecting said magnetic coupling respectively with first and second electromagnets.

47. The exposure mechanism of claim 45 in which said driven means comprises: i

a spooling cam, coupled in driven relationship with said electric motor; and

cam follower means associated with said spooling cam for deriving said reciprocal motion. 

1. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture, comprising: a first magnetic armature movable between initial and terminal positions; a first electromagnet selectively energizable at different levels to retain said first armature in its initial position and to permit said first armature to move to its terminal position; first means responsive to the movement of said first armature from its initial position to its terminal position to effect the determination of a first photographic function; a second magnetic armature movable between initial and terminal positions; a second electromagnet energizable at different levels to retain said second armature in its initial position and to permit said second armature to move to its terminal position; second means responsive to the movement of said second armature from its initial position to effect the determination of a second photographic function; and a master actuator movable in one direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets and movable in another direction to cause the commencement of said first photographic function.
 2. The exposure control mechanism of claim 1 in which said master actuator includes resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when in said initial positions.
 3. The exposure control mechanism of claim 2 including retaining means for holding said master actuator in a position compressibly retaining said first and second magnetic armatures in said initial positions.
 4. The exposure control mechanism of claim 3 including manually operated means for selectively releasing said retaining means from holding engagement with said master actuator.
 5. The exposure control mechanism of claim 2 wherein said resilient means are configured and arranged to permit said master actuator to continue to be moved in said one direction after causing the said engagement of said armatures with said electromagnets.
 6. The exposure control mechanism of claim 2 wherein said master actuator movement is pivotal about an axial mounting positioned substantially at one end thereof.
 7. The exposure control mechanism of claim 5 in which: said master actuator includes resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when in said initial positions; and including a mechanical latch selectively engageable with said master actuator when said actuator provides for the compressive engagement of said first and second magnetic armatures.
 8. The exposure control mechanism of claim 7 wherein said resilient means are configured and arranged to permit said master actuator to continue to be moved in said one direction after causing the said engagement of said armatures with said electromagnets.
 9. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture, comprising: a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween; a first magnetic armature movable between initial and terminal positions; a first electromagnet selectively energizable at different levels to retain said first armature in its initial position and to cause said first armature to move to its terminal position; first means responsive to the movement of said first armature from its initial position for controlling the said movement of said diaphragm assembly element to effect a determination of exposure aperture area; a second magnetic armature movable between initial and terminal positions; a second electromagnet energizable at different levels to retain said second armature in its initial position and to cause said second armature to move to its terminal position; second means responsive to the movement of said second armature from its initial position to effect the determination of said exposure interval; and a master actuator movable in one direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets and movable in another direction to cause said diaphragm assembly element to move from said initial position.
 10. The exposure control mechanism of claim 9 in which said master actuator is configured having resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when in said initial positions.
 11. The exposure control mechanism of claim 10 including manually releasable first latch means for mechanically retaining said master actuator in a preexposure position compressibly retaining said first and second armatures in said initial positions.
 12. The exposure control mechanism of claim 11 wherein said resilient means are configured and arranged to permit said master actuator to be moved in said one direction after causing the said compressive engagement of said armature with said electromagnets and following said manually releasable first latch means mechanical engagement.
 13. The exposure control mechanism of claim 11 including switch means mounted for actuation by said master actuator simultaneously as said actuator causes the commencement of movement of said diaphragm blade element for causing the initiation of a signal coincident with the said commencement Of said element movement.
 14. The exposure control mechanism of claim 11 including second latch means mechanically engageable with said diaphragm assembly element to retain it in said initial position configured and arranged with respect to said master actuator to respond to its said other directional movement for selectively releasing said element for movement from said initial position.
 15. The exposure control mechanism of claim 14 wherein said second latch means is configured and arranged to be driven out of said mechanical engagement with said diaphragm assembly element upon contact with said master actuator during its said other directional movement.
 16. The exposure control mechanism of claim 15 including switch means mounted for actuation by said master actuator simultaneously with said second latch means contact for causing the initiation of a signal substantially in coincidence with the said release of said diaphragm element.
 17. The exposure control mechanism of claim 11 wherein said master actuator is configured and arranged for pivotal movement about an axial mounting positioned substantially at one end thereof.
 18. The exposure control mechanism of claim 17 including cocking means operative to engage said master actuator at a position remote from said axial mounting for causing said one directional movement while deriving leverage about said mounting.
 19. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture comprising: a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween; a first magnetic armature movable between initial and terminal positions; a first electromagnet selectively energizable at different levels to retain said first armature in its initial position and to cause said first armature to move to its terminal position; first means responsive to the movement of said first armature from its initial position for controlling the said movement of said diaphragm assembly element to effect a determination of exposure aperture area; a second magnetic armature movable between initial and terminal positions; a second electromagnet energizable at different levels to retain said second armature in its initial position and to cause said second armature to move to its terminal position; second means responsive to the movement of said second armature from its initial position to effect the determination of said exposure interval; a master actuator movable about a fixed pivot in a first direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets and movable in a second direction to cause said diaphragm assembly element to move from said initial position; and cocking means operative to selectively engage said master actuator for causing said pivotal movement in said first direction following an exposure interval and for returning said diaphragm element to said initial position.
 20. The exposure control mechanism of claim 19 in which said master actuator includes resilient means contactable with said first and second magnetic armatures for causing their compressive engagement respectively with said first and second electromagnets when retained in said initial positions by said master actuator.
 21. The exposure control mechanism of claim 20 including manually releasable first latch means for mechanically retaining said master actuator in a preexposure position compressibly retaining said first and second armatures in said initial positions.
 22. The exposure control mechanism of claim 21 wherein said cocking means is operative to engage said master actuator at a position remote from said pivot so as to achieve a leverage for lowering the force values required to cause said first directional movemenT.
 23. The exposure control mechanism of claim 22 in which said cocking means includes: driven means actuable to provide said engagement with said master actuator and for urging said diaphragm element into said initial position; and driving means for selectively actuating said driven means following a said exposure interval.
 24. The exposure mechanism of claim 22 in which said cocking means includes: an electric motor selectively energizable to provide a rotational motion; driven means for converting said rotational motion into linear motion reciprocable within predetermined limits of travel; and means for selectively coupling said driven means with said master actuator at said remote position to cause said first directional movement.
 25. The exposure control mechanism of claim 24 wherein said driven means limit of travel is predetermined to permit said master actuator to be moved in said first direction a select distance after causing the said compressive engagement of said armature with said electromagnets and following said manually releasable first latch means engagement.
 26. The exposure control mechanism of claim 24 wherein said driven means includes: a spooling cam coupled in driven relationship with said electric motor; and cam follower means associated with said spooling cam for deriving said reciprocal motion.
 27. The exposure control mechanism of claim 24 wherein said coupling means includes a ram member linked at one end with said driven means and engageable at another end with said master actuator at said remote position for selectively transferring said linear motion to said master actuator when moving in said first direction.
 28. The exposure control mechanism of claim 27 wherein said ram member includes adjustable means for selectively varying the maximum extent of said first directional movement of said master actuator.
 29. The exposure control mechanism of claim 26 wherein said cocking means includes: a pivotally mounted bell crank assembly having a first portion linked in driven relationship with said cam follower means and a second portion engageable with said diaphragm assembly movable element for causing the return of said element to said initial position during the actuation of said driven means.
 30. An exposure control mechanism for controllably varying both the effective area of an exposure aperture and the exposure interval during which light passes through such aperture, comprising: a diaphragm assembly having at least one element movable from initial to terminal positions for varying effective aperture areas therebetween; a regulator arm movable between initial and terminal positions; means for biasing said regulator arm away from said initial position; a first magnetic armature mounted upon said regulator arm and movable therewith between said initial and terminal positions; a first electromagnet engageable for magnetic coupling with said first armature when said regulator arm is in said initial position and selectively energizable at different levels to retain said arm in its initial position by magnetic coupling therewith and to release said first armature to cause said arm to move under said bias to said terminal position; means responsive to the movement of said regulator arm from its initial position for controlling said movement of said diaphragm assembly element to effect a determination of exposure aperture area; a shutter assembly having at least one element movable from initial to terminal positions to effect the determination of said exposure interval; means for biasing said shutter element between said initial and terminal positions; a shutter regulator movable from an initial position retaining said shutter element in said initial position to a rest position permitting the said shutter element movement; a second magnetic armature mounted upon said shutter regulator and movable therewith between said initial and rest positIons; a second electromagnet engageable for magnetic coupling with said second armature when said regulator is in said initial position and selectively energizable at different levels to retain said regulator in its initial position by said magnetic coupling and to release said second armature to permit said regulator to move toward said rest position; a master actuator movable about a fixed pivot in a first direction to maneuver said first and second magnetic armatures respectively into engagement for magnetic coupling with said first and second electromagnets, thereby causing a corresponding movement of said regulator arm and said shutter regulator to said initial positions, and movable in a second direction to cause said diaphragm assembly element to move from said initial position; and cocking means operative to selectively engage said master actuator for causing said pivotal movement in said first direction following an exposure interval and for returning said diaphragm element and said shutter element to said initial positions.
 31. The exposure control mechanism of claim 30 wherein said master actuator includes resilient means engageable with said first and second magnetic armatures for urging said armatures into said compressive engagement during said first directional movement.
 32. The exposure control mechanism of claim 31 including master actuator latch means for selectively retaining said master actuator in a preexposure position retaining said first and second armatures in said compressive engagement with said first and second electromagnets and actuable to release said master actuator for movement in said second direction.
 33. The exposure control mechanism of claim 31 including: a master actuator latch pivotally biased for mechanical latching engagement with said actuator when in a preexposure position retaining said first and second armatures in said compressive engagement; and a manually actuable release member configured and arranged with respect to said master actuator latch to pivot said latch against said bias so as to cause the release of said mechanical latching engagement for initiating said second directional movement.
 34. The exposure control mechanism of claim 32 including diaphragm latch means responsive to said master actuator second directional movement for releasably retaining said diaphragm assembly element in said initial position although actuated by said master actuator.
 35. The exposure control mechanism of claim 32 including a diaphragm latch pivotally mounted within said mechanism and biased toward latching engagement with said diaphragm element when in said initial position, said latch being configured and arranged to be driven out of said engagement by said master actuator in response to the second directional movement thereto.
 36. The exposure control mechanism of claim 32 in which said shutter regulator includes an arm member engageable with said shutter assembly element when in said initial position and mounted for movement toward said raised position codirectionally with the movement of said element.
 37. The exposure control mechanism of claim 32 wherein said cocking means is operative to engage said master actuator at a position remote from said pivot so as to achieve a leverage for lowering the force values required to cause said first directional movement.
 38. An exposure mechanism for a photographic camera comprising: a camera housing for mounting the optical path instrumentalities of said camera; a diaphragm mechanism including at least two aperture blade elements mounted upon said housing, said elements being mutually and synchronously coactive and releasable for movement between cocked and rest terminal positions defining minimum and maximum exposure apertures first spring means for urging said blade elements between said terminal positions; regulator means movable from cocked to terminal orientations for halting the movement of said aperture blade elements At positions defining select exposure apertures; second spring means for urging said regulator means from said cocked toward said terminal orientations; a first electromagnet mounted upon said housing in an orientation permitting its engagement for magnetic coupling with said regulator means when in said cocked orientation, said electromagnet being selectively energizable for controlling the said movement of said regulator means; a shutter mechanism having at least one element movable from a cocked to a blocking terminal orientation relative to said optical path to effect the determination of the interval of an exposure; a third spring means for urging said shutter element between said cocked and terminal positions; shutter latch means mounted upon said housing and movable into orientations for retaining said shutter element in and releasing it from said cocked position; a second electromagnet configured and arranged on said housing to permit its engagement for magnetic coupling with said shutter latch means and being selectively energizable for controlling said latch means movement from said element retaining orientation; a master actuator rotatably mounted upon said housing for movement about a fixed pivot in first and second directions and configured and arranged to cause the engagement for magnetic coupling of said first electromagnet with said regulator means and of said second electromagnet with said shutter latch means when moved in said first direction, and to cause the said release of said aperture blade elements when moved in said second direction; manual release means for causing said master actuator to move in said second direction; and cocking means mounted upon said housing for selectively causing said master actuator to move in said first direction and for repositioning said aperture blade elements to cocked terminal positions and said shutter mechanism element to said cocked terminal orientation.
 39. The exposure mechanism of claim 38 in which said master actuator is configured having resilient means, contactable with said regulator means and said shutter latch means for causing their engagement respectively with said first and second electromagnets when in said cocked positions.
 40. The exposure mechanism of claim 39 wherein said cocking means is operative to engage said master actuator at a position remote from its pivotal mounting so as to achieve a leverage for lowering force values required to cause said first directional movement.
 41. The exposure mechanism of claim 40 including a master actuator latch pivotally mounted upon said camera housing and biased for mechanical latching engagement with said master actuator when said actuator is in a preexposure orientation retaining said regulator means and said shutter latch means in said engagement for magnetic coupling.
 42. The exposure mechanism of claim 40 including diaphragm latch means responsive to said master actuator second directional movement for releasably retaining said aperture blade elements in said cocked position until actuated by said master actuator.
 43. The exposure mechanism of claim 42 including switch means mounted upon said housing and oriented for actuation by said master actuator simultaneously with said diaphragm latch means contact for causing the initiation of a signal simultaneously with said release of said aperture blade elements.
 44. The exposure mechanism of claim 42 in which said diaphragm latch means comprises: a latching element configured having a latching tip and a striking flange, said tip being engageable with at least one said aperture blade element and said flange being contactable with said master actuator at or during second directional movement; and means for biasing said element into pivotal engagement with said aperture blade element.
 45. The exposure mechanism of claim 42 in which said cocking means includes: electric motor selectively energizable to provide a rotational motion; driveN means for converting said rotational motion into linear motion reciprocable within predetermined limits of travel; means for selectively coupling said driven means with said master actuator remote position to cause said first directional movement; a pivotally mounted bell crank assembly having a first portion linked with said driven means and a second portion engageable with at least one said aperture blade element for selectively positioning said element in said cocked position; and a cocking arm linked in driven relationship with said bell crank assembly and configured and arranged on said housing for urging said shutter element into said cocked orientation.
 46. The exposure mechanism of claim 42 in which said regulation means and said shutter latch means include magnetic armatures for effecting said magnetic coupling respectively with first and second electromagnets.
 47. The exposure mechanism of claim 45 in which said driven means comprises: a spooling cam, coupled in driven relationship with said electric motor; and cam follower means associated with said spooling cam for deriving said reciprocal motion. 